On Friday 19 July 2002 03:03, Terry Koyama wrote: >This is a continuation of my earlier problem which >still exists: >Garbage in Amanda tape headers - >http://groups.yahoo.com/group/amanda-users/message/36902. > >So what I did was break down the problem to isolate >the problem. I got a blank tape, wrote a file to it >and read it back out. The file that was returned from >the tape was corrupted with garbage in certain areas. > >I must be going insane! What would be the cause of >this? Block sizes? Faulty tape drive? Faulty tape? >SCSI related? > >Anyway, here are the details: > >1. Created file1.txt with some random text. > >2. Ran these commands. I don't know what the block > size is suppose to be but I've tried many > different ones which results in the same outcome. > (I've also done this with tar...same results). > >> dd if=file1.txt of=/dev/st0 >> >> dd if=/dev/st0 of=file2.txt >> >> more file1.txt > >Jolie Files for Divorce from Thornton >Thu Jul 18, 4:31 PM ET > >By Steve Gorman > >LOS ANGELES (Reuters) - Oscar-winning actress Angelina >Jolie has filed for divorce from her husband of two >years, Billy Bob Thornton, according to court >documents made public on Thursday. > >Representatives for Jolie, 27, could not immediately >be reached for comment, but a spokesman for Thornton, >46, said the only comment from the actor-writer and >musician was, "It's a sad thing." > ><snip> > >> more file2.txt > >Jolie Files for Divorce from Thornton >Thu Jul 18, 4:31 PM ET > >By Steve Gorman > >LOS ANGELES (Reuters) - Oscar-winning actress Angelina > >Jolie has filed for divorce from her husband of two >years, Billy Bob Thornton, according to court >documents made public on Thursday. Representatives >for Jolie, 27, could not immedi`tdl ` `aa``d fb >cmmedd$ `tp`oaeqe`$ fgp Thorltol, 46, said the only >comment from the actor-writer and musician was, "It's >a sad thing." > ><snip> > >> file file1.txt > >file1.txt: English text > ># note: I only mention this because with other files, ># file2.txt was labeled as "ASCII text" > >> file file2.txt > >file2.txt: English text > >>diff file1.txt file2.txt > >Binary files file1.txt and file2.txt differ > >---------------------------------------- > >H/W Specs: >SCSI storage controller: Adaptec AHA-2940U2/W / 7890 >(rev 01) >HP SureStore 1559C DAT Autoloader Tape Drive DAT24x6e >(DDS-3). >HP DDS-3 C5708A 24GB tapes > >S/W Specs: >Debian Linux 2.2.18pre21 >dd (GNU fileutils) 4.0l >Turned h/w compression off. > >Thanks, > >Terry
You've covered most of the bases with your question I think, and my own first guess would be a bad tape. "Is this repeatable with another tape?" is the obvious next Q. Then next would be bad buffer ram in the drive, which could be defined by using a file thats the same size as the buffer, and piddling with the driver so it wrote that full buffers worth in one huge write. But that would take a 'more better' programmer than I to do. And the drive would probably lock the write before it was 100% done to prevent the impending circular buffer pointer overflows. You wouldn't see that in the log (I don't think) even with verbose scsi error reporting turned on in the kernel. The errors placement doesn't appear to be random, but bursty, and that, in my mind, would tend to rule out scsi bus parity and termination errors. If that actually was the case, you could recompile the kernel and add the verbose scsi error reporting option which should then log all detected bus errors. With this 'set of data' thats my best shot. -- Cheers, Gene AMD K6-III@500mhz 320M Athlon1600XP@1400mhz 512M 99.07% setiathome rank, not too shabby for a WV hillbilly
